The CIA determined Thursday that the voice on a tape claiming preparation for an al-Qaida attack on the United States was that of Osama bin Laden, an agency official said. The audio tape, played by the Arab network Al-Jazeera, was the first public communication from the terror group's leader since December 2004. "Following technical analysis of the Osama bin Laden tape aired today, the CIA assesses that it was the voice of Osama bin Laden," said the agency official, speaking on condition of anonymity because the official was not authorized to speak by name. The official provided no details about how the Central Intelligence Agency concluded that the voice was that of bin Laden. US counterterror officials said despite the tape they have seen no specific or credible intelligence to indicate an upcoming al-Qaida attack on the country. A US counterterror official said analysts had no reason to doubt an assessment by Al-Jazeera that the tape was recorded in the Islamic month that corresponds with December.